Process for providing coatings on a metallic surface

Abstract

Sequentially applying two different coatings, in two steps, to metallic surfaces. Metallic surfaces are contacted at temperatures from 10-100° C. with aqueous solution A and then with aqueous solution B, or vice versa, wherein solution A contains an effective amount of zirconium, hafnium, titanium, silicon and/or boron, and of fluoride as ions and/or complex ions able to pickle metallic surfaces and generate a coating on the pickled metallic surface and that solution B contains an effective amount of one or more of XYZ, X*Y*Z* and/or X*Y*Z*Y*X* where Y is an organic group with 2-50 carbons, where X as well as Z is a group—each same or different—of OH—, SH—, NH 2 —, NHR—, CN—, CH═CH 2 —, OCN—, CONHOH—, COOR′, acrylamide-, epoxide-, CH 2 ═CR″—COO—, COOH—, HSO 3 —, HSO 4 —, (OH) 2 PO—, (OH) 2 PO 2 —, (OH)(OR′)PO—, (OH)(OR′)PO 2 —, SiH 3 —, Si(OH) 3 —, where R′ is an alkyl group with 1-4 carbons, where R″ is hydrogen or an alkyl group with 1-4 carbons, and where X and Z are each bound to the Y in their terminal position, where Y* is an organic group with 1-30 carbons, where X* as well as Z* is a group—each same or different—of OH—, SH—, NH 2 —, NHR′—, CN—, CH═CH 2 —, OCN—, CONHOH—, COOR′, acrylamide-, epoxide-, CH 2 ═CR″—COO—, COOH—, HSO 3 —, HSO 4 —, (OH) 2 PO—, (OH) 2 PO 2 —, (OH)(OR′)PO—, (OH)(OR′)PO 2 —, SiH 3 —, Si(OH) 3 —,N—CH 2 —PO(OH) 2 —, —N—[CH 2 —PO(OH) 2 ] 2 — where R′ is an alkyl group with 1-4 carbons, where R″is hydrogen or an alkyl group with 1-4 carbons.

What is claimed is:  
     
       1. A process for treating a metallic surface having at least two separate but sequential steps for applying two different coatings, including contacting said metallic surface with aqueous solution A and then with aqueous solution B, or with aqueous solution B and then with aqueous solution A, at a temperature in the range of from 10 to 100° C., wherein 
       solution A contains an amount of zirconium, hafnium, titanium, silicon and/or boron, and an amount of fluoride in the form of ions and/or complex ions, capable of pickling the metallic surface and generating a coating on the pickled metallic surface, and wherein solution B contains an effective amount of one or more compounds of the type XYZ, X*Y*Z* and/or X*Y*Z*Y*X*  
       where Y is an organic group with 2 to 50 carbon atoms,  
       X and Z are each the same or different and are selected from the group consisting of OH—, SH—, NH 2 —, NHR′—, CN—, CH═CH 2 —, OCN—, CONHOH—, COOR′, acrylamide-, epoxide-, CH 2 ═CR″—COO—, COOH—, HSO 3 —, HSO 4 —, (OH) 2 PO—, (OH) 2 PO 2 —, (OH)(OR′)PO—, (OH)(OR′)PO 2 —, SiH 3 —, and Si(OH) 3 —,  
       R′ is an alkyl group with 1 to 4 carbon atoms,  
       R″ is a hydrogen atom or an alkyl group with 1 to 4 carbon atoms,  
       and X and Z are each bound to Y in their terminal position,  
       Y* is an organic group with 1 to 30 carbon atoms,  
       and X* and Z* are each the same or different and are selected from the group consisting of OH—, SH—, NH 2 —, NHR′—, CN—, CH═CH 2 —, OCN—, CONHOH—, COOR′, acrylamide-, epoxide-, CH 2 ═CR″—COO—, COOH—, HSO 3 —, HSO 4 —, (OH) 2 PO—, (OH) 2 PO 2 —, (OH)(OR′)PO—, (OH)(OR′)PO 2 —, SiH 3 —, Si(OH) 3 —, N—CH 2 —PO(OH) 2 —, and —N—[CH 2 —PO(OH) 2 ] 2 —.  
       where R′ is an alkyl group with 1 to 4 carbon atoms,  
       where R″ is a hydrogen atom or an alkyl group with 1 to 4 carbon atoms.  
     
     
       2. The process of  claim 1 , wherein X* and Z* are each bound to the group Y* in their terminal positions. 
     
     
       3. The process of  claim 1 , wherein the metallic surface consists essentially of aluminum, copper, iron, magnesium, zinc or of an alloy containing aluminum, copper, iron, magnesium, silicon and/or zinc. 
     
     
       4. The process of  claim 1 , wherein compounds of the type XYZ, X*Y*Z* and/or X*Y*Z*Y*X* are able to form self assembling molecules, which molecules are capable of forming a layer, including a monolayer, of assembling molecules on a metallic surface. 
     
     
       5. The process of  claim 1 , wherein Y or Y* is a linear unbranched group. 
     
     
       6. The process of  claim 1 , wherein Y or Y* is a linear group branched with one or more alkyl group or aromatic group. 
     
     
       7. The process of  claim 1 , wherein solution B includes one or more of XYZ, X*Y*Z* and X*Y*Z*Y*X* with a group Y or Y* that has an even number of carbon atoms. 
     
     
       8. The process of  claim 1 , wherein at least one of XYZ, X*Y*Z* and X*Y*Z*Y*X* is present in the aqueous solution as salt and/or acid. 
     
     
       9. The process of  claim 1 , wherein solution B includes one or more of XYZ, X*Y*Z* and X*Y*Z*Y*X*, and Y or Y* is an unbranched straight-chain alkyl group with 3 to 30 carbon atoms. 
     
     
       10. The process of  claim 1 , wherein solution B includes one or more of XYZ, X*Y*Z* and X*Y*Z*Y*X*, and Y or Y* is an unbranched straight-chain group consisting of 1 to 4 aromatic C 6 H 4  nuclei connected in the para-position, or a group consisting of 1 or 2 unbranched, straight-chain alkyl residues each with 1 to 12 carbon atoms or 1 to 4 aromatic C 6 H 4  nuclei connected in the para-position. 
     
     
       11. The process of  claim 1 , wherein solution B includes one or more of XYZ, X*Y*Z* and X*Y*Z*Y*X*, and Y or Y* is an unbranched, straight-chain alkyl group with 6 to 14 carbon atoms or a p-CH 2 —C 6 H 4 —CH 2 -group or a p,p′-C 6 H 4 —C 6 H 4 -group. 
     
     
       12. The process of  claim 1 , wherein solution B includes one or more of XYZ, X*Y*Z* and X*Y*Z*Y*X*, and group (OH) 2 PO 2 — or (OH)(OR′)PO 2 — as X or X*. 
     
     
       13. The process of  claim 1 , wherein solution B includes one or more XYZ, X*Y*Z* and X*Y*Z*Y*X* with a group (OH) 2 PO 2 —, (OH)(OR′)PO 2 —, OH—, SH—, NHR′—, CH═CH 2  or CH 2 ═CR″—COO— as Z or Z*. 
     
     
       14. The process of  claim 1 , wherein XYZ, X*Y*Z* and/or X*Y*Z*Y*X* are in an aqueous solution containing at least one compound selected from the group consisting of 
       1 -phosphonic acid-1 2-mercaptododecane,  
       1-phosphonic acid-12-(N-ethylamino)dodecane,  
       1-phosphonic acid-12-dodecene,  
       p-xylene diphosphonic acid,  
       1,10-decanediphosphonic acid,  
       1,12-dodecanediphosphonic acid,  
       1,14-tetradecanediphosphonic acid,  
       1-phosphoric acid-12-hydroxydodecane,  
       1-phosphoric acid-12-(N-ethylamino)dodecane,  
       1 -phosphoric acid-12-dodecene,  
       1-phosphoric acid-12-mercaptododecane,  
       1,10-decanediphosphoric acid,  
       1,12-dodecanediphosphoric acid,  
       1,14-tetradecanediphosphoric acid,  
       p,p′-biphenyldiphosphoric acid,  
       1-phosphoric acid-12-acryloyldodecane,  
       1,8-octanediphosphonic acid,  
       1,6-hexanediphosphonic acid,  
       1,4-butanediphosphonic acid,  
       1,8-octanediphosphoric acid,  
       1,6-hexanediphosphoric acid,  
       1,4-butanediphosphoric acid,  
       aminetrimethyleneposphonic acid,  
       ethylenediaminetetramethylenephosphonic acid,  
       hexamethylenediaminetetramethylenephosphonic acid,  
       diethylenetriaminepentamethylenephosphonic acid and  
       2-phosphonobutane-1,2,4-tricarboxylic acid.  
     
     
       15. The process of  claim 1 , wherein the metallic surfaces are contacted with the solution A in the time range of from 0.001 seconds to 10 minutes. 
     
     
       16. The process of  claim 1 , wherein the pH value of the solution A is in the range of from 0.5 to 6. 
     
     
       17. The process of  claim 1 , wherein in solution A the concentration of the chemical elements selected from the group of titanium, zirconium, hafnium, silicon and boron is in the range of from 0.0001 to 0.2% by weight. 
     
     
       18. The process of  claim 1 , wherein in solution A the concentration of the zirconium, if present, is in the range of from 0.0001 to 0.1% by weight, the concentration of the titanium, if present, is in the range of from 0.0001 to 0.1% by weight, and wherein only one of titanium and zirconium must be present. 
     
     
       19. The process of  claim 1 , wherein in solution A the concentration of the total fluoride is in the range of from 0.001 to 0.2% by weight calculated as fluoride. 
     
     
       20. The process of  claim 1 , wherein a coating comprising solution A, solution B, or a combination of both solution A and solution B, is generated having a coating weight measurable by X-ray spectroscopy. 
     
     
       21. The process of  claim 1 , wherein the metallic surface is contacted with the solution A, or with the solution B, or with both, by dipping, immersing, roll-coating, squeegeeing or spraying. 
     
     
       22. The process of  claim 1 , wherein the time of contacting the metallic surfaces with the solution B is 0.5 second to 10 minutes. 
     
     
       23. The process of  claim 1 , wherein the pH value of solution B is in the range of from 1 to 10. 
     
     
       24. The process of  claim 1 , wherein one or both aqueous solutions contain a proportion of an organic solvent. 
     
     
       25. The process of  claim 1 , wherein before applying the first aqueous solution, the metallic surface is subject to one or more of cleaning, degreasing, pickling and pre-annealing. 
     
     
       26. The process of  claim 1 , wherein there is at least one additional step of rinsing the metal surface with water. 
     
     
       27. The process of  claim 1 , wherein there is an additional step of rinsing between contacting the metallic surface with solution A and contacting the surface with solution B. 
     
     
       28. The process of  claim 1 , wherein either the coated metallic surface is dried, the excess liquid is blown away, or both, after having been coated with solution B. 
     
     
       29. The process of  claim 1 , wherein the metallic surface coated with solutions A and B are then coated with one or more of a lacquer, a paint, an adhesive, an after rinse, a sealant, a rubber and an organic material. 
     
     
       30. The process of  claim 1 , wherein the metallic surface is coated with a multilayer of at least 3 layers by alternately applying solutions A and B. 
     
     
       31. The process of  claim 1 , wherein a metallic surface of castings, extruded parts, forgings, frames, housings, profiles, sheet stock, stampings, strips, wheels, wires, parts for aircraft industry, for automobile industry, for beverage or other containers, for construction or for mechanical engineering is treated.